Michael--
It only takes only one upper filters or a lower filters value usually
conferred by 3rd party software to screw things up and both of them are
often not present. The original KB article on this is a very frequent
remedy for the cause that the CD or DVD drive can't be accessed and
sometimes it will show in Dev Manager.
The Guided Help KBs are interesting. I know that Vista is using Guided Help
and building some of it in the next few months and thinking about extending
it to other applications like Office. I didn't know that Guide Help KBs
were around though.
CH